The present disclosure generally relates to particle disengagement devices. More specifically, in certain embodiments the present disclosure relates to particle disengagement devices useful in separation vessels and associated methods and systems.
In a typical Fluid Catalytic Cracking Unit (FCCU), finely divided regenerated catalyst is drawn from a regenerator through a regenerator standpipe and contacts with a hydrocarbon feedstock in a lower portion of a reactor riser. Hydrocarbon feedstock and steam enter the riser through feed nozzles. The mixture of feed, steam and regenerated catalyst, which has a temperature of from about 200° C. to about 700° C., passes up through the riser reactor, converting the feed into lighter products while a coke layer deposits on the surface of the catalyst, temporarily deactivating the catalyst.
The hydrocarbon vapors and catalyst from the top of the riser are then passed through cyclones to separate spent catalyst from the hydrocarbon vapor product stream. The spent catalyst enters a stripper where steam is introduced to remove hydrocarbon products from the catalyst. The spent catalyst then passes through a spent catalyst standpipe to enter the regenerator where, in the presence of gas and at a temperature in the range of from about 620° C. to about 760° C., the coke layer on the spent catalyst is combusted to restore the catalyst activity. Regeneration is typically performed in a vessel comprising a fluidized bed and one or more cyclones.
Currently, the cyclone loadings are designed to manage the full bed entrainment rate. However, amount of wear is proportional to loading rate. Thus, cyclones with high loading rates are susceptible to high rates of wear.
It is desirable to develop a way of reducing the cyclone loading rate in separation vessels to extend the life of cyclones.